After hearing the driveshaft horror stories, I populated my Gren's toolbox with an IR gun. The CV joints at either driveshaft didn't reveal anything out of ordinary.
Last Saturday I had several extended SoCal highway runs - with air temperature around 75F and typical I-5 speeds. I got under and hit the centers of the diff covers with the IR gun: the front read between 50 and 55C (122-131F), but the rear - 80 to 83C (176-181F). None are a cause for any concern, but a 30C (55F) difference is unexpected. I could speculate that the front diff is exposed to ambient air and rear - to the warm wash from the transmission, transfer case, and immediate muffler vicinity. Still, 30C is a big step.
The only other difference is the skidplate under the rear diff. I will take it off for a highway drive just to see if it makes any difference - post the results when that happens.
Whatever the cause is, I need to revisit my maintenance schedule. Changed the oil in the rear diff (first change - 12k, now 46k) - oil came out clean, no iron shavings on the plug.
I'll probably punch a few 1-2" holes in the transmission skidplate as well.
Last Saturday I had several extended SoCal highway runs - with air temperature around 75F and typical I-5 speeds. I got under and hit the centers of the diff covers with the IR gun: the front read between 50 and 55C (122-131F), but the rear - 80 to 83C (176-181F). None are a cause for any concern, but a 30C (55F) difference is unexpected. I could speculate that the front diff is exposed to ambient air and rear - to the warm wash from the transmission, transfer case, and immediate muffler vicinity. Still, 30C is a big step.
The only other difference is the skidplate under the rear diff. I will take it off for a highway drive just to see if it makes any difference - post the results when that happens.
Whatever the cause is, I need to revisit my maintenance schedule. Changed the oil in the rear diff (first change - 12k, now 46k) - oil came out clean, no iron shavings on the plug.
I'll probably punch a few 1-2" holes in the transmission skidplate as well.
I suspect it won't make much 
